1. Field of the Invention
This invention pertains to a cylinder head configuration and to shapes for use in the cylinder head. The application is for use in intake and exhaust valve configurations flat head engines. The combustion chamber shape and gas flow through the combustion chamber results in an increase of combustion efficiency, a reduction of hydrocarbon emissions and an increase in compression ratio.
2. Description of the Related Art
It has been known to provide four cycle engines with side valve, xe2x80x9cL-headxe2x80x9d or flat head type cylinder heads with integral combustion chambers, hereinafter xe2x80x9cflatheadxe2x80x9d engines. The flat head engine has a head with a cavity formed in it. This cavity provides the combustion chamber for the engine.
A combustable fluid, such as a mixture of air and fuel, is directed to the combustion chamber through an intake valve. An exhaust valve allows spent gasses through a passage to an exhaust manifold and the exhaust is thus evacuated from the combustion chamber.
The flat head engine was in widespread use through the 1950""s, including automotive use, for many years but has been superceded in many applications by overhead valve engines. The flat head engine is widely used, however, in small displacement four cycle engines with one or two cylinders. Typical applications for four cycle flat head engines are found in gas operated lawn mowers, electric generator power systems, snowblowers, weed trimmers, lawn edgers, go kart motors, boat engines and the like.
There have been many intake/exhaust/valve configurations in the development of the flat head engine. Many of these valve configurations use slide valves, shuttle valves or poppet valves.
For instance, a flat head engine with a poppet valve configuration is shown in U.S. Pat. No. 1,784,555. A slide type valve, a piston type valve and a sleeve type valve are shown in U.S. Pat. Nos. 1,856,348; 1,680,099 and 1,922,678. None of these patents show the valve configuration presented herein.
The age of these patents and the paucity of modern day patents concerning valve systems for flat head engines show that there has been a dearth in the generation of ideas relating to flat head engines. This invention is directed to a system that makes the four cycle flat head engine more competitive with the overhead valve and overhead camshaft engines in vogue and being developed today. The overhead valve engines are more expensive to produce than the flat engine and there are great advantages in production economics if an improvement can be made in the efficiency and especially in reducing hydrocarbon emissions of the flat head engine.
One advantage of this invention is that hydrocarbon emissions are reduced to the point where small engine manufacturers can produce a clean burning engine without having to resort to an overhead valve configuration to get equivalent hydrocarbon emissions.
The invention is a cylinder head for use and a flat head type four cycle engine. A combustion chamber is formed in the head. A poppet valve having a cup shaped extension extending from the face of the valve will move into and partially through the combustion chamber in order to allow gas to enter and exit the combustion chamber.
The cup of the valve will move into and out of a recess formed in the cylinder head in line with the valve. The cup surface and the valve cup receiving recess will be a sealed sliding fit so that the valve cup displacement does not affect the volume of the combustion chamber.
The valve cup eliminates the need for a displaceable volumn above the valve faces in the combustion chamber allowing better use and configuration of the combustion chamber.
In one embodiment of the invention the valve cup receiving recess is provided with a liner bore to line the recess. This allows the use of alternative sealing structures, metal compounds and modifications to valve sizing when using a standard head for engines with a choice of valve diameters.
One object of this invention to increase the efficiency of an internal combustion engine and decrease the hydrocarbon emissions of such engine.
Another object of this invention to increase the compression ratio of an engine.
It is also an object of this invention to provide a valve system that can be installed on a contemporary engine without significant engine modification.
It is also an object of this invention to provide a lightweight valve cup.
Another object of this invention to provide a two piece valve system with a valve having cup portion.
A further object of this invention to provide a construction of a valve stem and cup valve using friction welding.
It is another object of the invention to provide a removable access cover on a head of a flat head engine.
It is also an object of the invention to provide communication from the face of an intake valve to the face of an exhaust valve.
The preferred embodiments of the invention presented here are described below in the drawing figures and Detailed Description of the Invention. Unless specifically noted, it is intended that the words and phrases in the specification and the claims be given the ordinary and accustomed meaning to those of ordinary skill in the applicable arts. If any other special meaning is intended for any word or phrase, the specification will clearly state and define the special meaning.
Likewise, the use of the words xe2x80x9cfunctionxe2x80x9d or xe2x80x9cmeansxe2x80x9d in the Detailed Description of the Invention is not intended to indicate a desire to invoke the special provisions of 35 U.S.C. 112, Paragraph 6, to define the invention. To the contrary, if the provisions of 35 U.S.C. 112, Paragraph 6 are sought to be invoked to define the inventions, the claims will specifically state the phrases xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d and a function, without also reciting in such phrases any structure, material or act in support of the function. Even when the claims recite a xe2x80x9cmeans forxe2x80x9d or xe2x80x9cstep forxe2x80x9d performing a function, if they also recite any structure, material or acts in support of that means or step, then the intention is not to invoke the provisions of 35 U.S.C. 112, Paragraph 6. Moreover, even if the provisions of 35 U.S.C. 112, Paragraph 6 are invoked to define the inventions, it is intended that the inventions not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function, along with any and all known or later-developed equivalent structures, material or acts for performing the claimed function.